JPH0450548A - Shift controller for automatic transmission - Google Patents

Abstract

PURPOSE:To reconcile the termination of both transmission parts each other by increasing the extent of back pressure in an accumulator when the shift termination of the transmission part at a high gear shifting side is estimated so as to be relatively later than that of the transmission part at a low gear shifting side. CONSTITUTION:There is provided such a means as capable of changing back pressure in each accumulator of frictional engagers of two transmission parts at the same time, while a relative progressive state in both these transmission parts is detected, and when a shift termination of the transmission part at a high-gear shifting side is estimated so as to be relatively later than that of the transmission part at a low-gear shifting side, the extent of back pressure in each accumulator is increased, so that the high-gear shifting side is accelerated of its shift, and the low-gear shifting side is made so as to be decelerated of its shift in consequence. Therefore both transmission parts can be controlled into each desirable direction by only operating the accumulator back pressure in common with these two transmission parts owing to one linear solenoid value, thus each shift termination of these transmission parts is synchronized.

Description

[Detailed description of the invention]

r Industrial Application Field of the Invention The present invention relates to an automatic transmission system in which first and second transmission sections capable of independently changing speeds are connected in series and each transmission section is shifted in opposite directions to achieve a specific speed change. The present invention relates to a speed change control device for a transmission.

[Prior art] Conventionally, a first transmission section that can switch between the first and third speeds, and a second transmission section that is arranged in series with the first transmission section that can switch between two high and low speeds have been used. An automatic transmission equipped with this is known. In such an automatic transmission, as shown in part A of FIG. It is possible to achieve multi-speed shifting. However, in such automatic transmissions, the first transmission section and It is possible for the second transmission sections to shift simultaneously and in opposite directions to achieve a specific upshift or downshift, but in this case it would be difficult to control the shifts of each transmission section individually. There is a risk that very strange shift characteristics may result, such as only a low gear shift remaining after a gear shift, or conversely, only a high gear shift remaining after a low gear shift. In view of this, each transmission section shifts in the opposite direction,
When an upshift is performed as a whole, the gear shift of the other transmission section with a large change in the gear ratio is hidden while the other gear shift is being shifted. It has been proposed to perform sea-fence control in which the speed change of the transmission section is started and completed. Furthermore, control has been proposed in which the end of the shift of both transmission sections is made to coincide with each other, rather than simply concealing it. To execute this concretely, for example, first issue a high gear shift command, then issue a low gear shift command at the same time as the actual start of the high gear shift is detected, and apply the engagement pressure of the friction engagement device on the low gear shift side ( By controlling the drain state), both shifts can be completed at the same time (
JP-A-62-317541゜ [Problem to be Solved by the Invention [1] However, in automatic transmissions in which simultaneous gear changes are performed, many proposals have been made regarding this type of sea fence control; When attempting to achieve advanced sea fence control that synchronizes the end of shifting between the S-shift section and the second transmission section, it is difficult to achieve this by simply controlling the engagement pressure of one transmission section. There has been a problem in that it is unable to respond to various variations in engine torque and automatic transmissions, and it may not be possible to perform advanced control such as synchronizing the end of the shift in both transmission sections. To solve this problem, in order to obtain more or less good results, it is necessary to provide separate linear solenoid valves that can arbitrarily control the engagement pressure for each of the two transmission parts, which would avoid the increase in costs. It had become nothing. The present invention was made in view of such conventional problems, and uses a single linear solenoid valve to satisfactorily control both the first transmission section and the second transmission section, thereby eliminating various variations. It is an object of the present invention to provide a shift control device for an automatic transmission that can easily and inexpensively realize sophisticated control such as matching the end of shift of both transmission sections regardless of the situation. [Means for Solving the Problems] The present invention provides an automatic transmission in which first and second transmission sections are connected in series and a specific speed change is achieved by shifting each transmission section in opposite directions. In the transmission control device, there is provided a means for simultaneously changing the back pressure of each of the accumulators of the friction engagement devices involved in the above-mentioned transmission of both transmission sections, and a means for simultaneously changing the back pressure of each accumulator of each of the frictional engagement devices involved in the above-mentioned shifting of both transmission sections; means for predicting in real time whether or not the end of the shift of the transmission section that will shift to a high gear will be relatively delayed from the end of the shift of the transmission section that will shift to a low gear. The above object is achieved by increasing the back pressure of the accumulator when it is predicted that there will be a delay. [Function] The present invention includes means for simultaneously changing the back pressures of the respective accumulators of the frictional engagement devices of both transmission sections, and detects the relative progress state of both transmission sections. The back pressure of the accumulator is increased when it is predicted that the end of the gear shift of the transmission section that is shifting gears is likely to be delayed by 1 relative to the end of the gear shift of the transmission section that is shifting to a low gear. ing. Due to this increase in accumulator back pressure, 2. A high gear shift (1-) speeds up the gear shift, and a low gear shift (S, low gear shift) allows the gear to be shifted or delayed. As a result, by simply manipulating the accumulator back pressure common to both transmission sections using a single linear solenoid valve, it is possible to control both transmission sections in their respective preferred directions, and the end of the shift of both transmission sections can be controlled. Advanced control such as synchronization can be performed easily. In addition, the present invention reduces the back pressure of the accumulator when it is predicted that the shift of the transmission section that will shift to a high gear will end relatively earlier than the end of the shift of the transmission section that will shift to a low gear. It naturally includes the idea of control. However, in implementation, it is not always necessary to control in both directions. For example, the initial value of the accumulator back pressure may be set to a low value, and only compensation in the increasing direction may be performed.

【Example】

Embodiments of the present invention will be described in detail below based on the drawings. FIG. 2 shows an overall outline of a vehicle automatic transmission to which this embodiment is applied. This automatic transmission includes a torque converter 2o, a second transmission section 40, and a first transmission section 6o with three forward speeds and one reverse speed. The torque converter 20 includes a pump 21 and a turbine 2.
2, a stator 23, and a lock-up clutch 24. The pump 21 is connected to the crankshaft 10 of the engine 1, and the turbine 22 is connected to a carrier 41 of a planetary gear device in the second transmission section 40. In the second transmission section 40, a planetary pinion 42 rotatably supported by the carrier 41 meshes with a sun gear 43 and a ring gear 44. Furthermore, a clutch C is provided between the sun gear 43 and the carrier 41.
A one-way clutch F o :/i' is provided, and a play-1i-Bo is provided between the sun gear 43 and the housing HIJ. The first transmission section 60 is provided with two rows of planetary gears, one on the front side and the other on the rear side. This planetary gear device includes a common sun gear 61, ring gear 62.63, planetary pinion 64.65,
and carrier 66.67. A ring gear 44 of the second transmission section 40 is connected to the ring gear 62 via a clutch C1. A clutch C2 is connected between the ring gear 44 and the sun gear 61.
Or is provided. Further, the carrier 66 is connected to the ring gear 63, and the carrier 66 and the ring gear 63 are connected to the output shaft 70. On the other hand, is there a play between the carrier 67 and the housing Hu? A brake B2 is provided between the sun gear 61 and the housing Hu via the one-way clutch F1, and a brake B2 is provided between the sun gear 61 and the housing Hu. 'Play'
r B 1 is provided. This automatic transmission includes a transmission section as described above, and includes a throttle/torque sensor 100 that detects the throttle opening θth that reflects the load condition of the engine 1;
The central processing unit (ECTJ) 104 receives signals from the vehicle speed sensor 102 and the like that detect the vehicle speed NO, and controls the oil pressure control circuit 106 according to a predetermined gear shift map.
The solenoid valves S1 to S3 inside are driven and controlled,
The combination of engagement of each clutch, brake, etc., as shown in part B of FIG. 3, is performed to perform speed change control. In addition, in Fig. 3, the O mark indicates the engaged state, and the X mark indicates that the shift lever becomes the engaged state only when the shift lever is moved to an engine brake range such as L range or 2 range. 4 As shown in FIG. 4, the solenoid valves S+ and Sz control the first and second shift valves of the first transmission section 60, and the solenoid valve S3 controls the first and second shift valves of the second transmission section 40. Controls the third shift valve that switches between the high speed side and the low speed side. Further, the solenoid valve SL is configured to control the lock-up clutch 24 of the torque converter 20 via a lock-up relay valve, and the linear solenoid valve SLN is configured to control the back pressure of the accumulator via an accumulator control valve. It is possible to arbitrarily control the engagement pressure during gear shifting. In FIG. 2, reference numeral 110 is a shift position sensor that detects the positions of N, D, R, etc. operated by the driver. Reference numeral 112 is a pattern select switch for economy pattern (economical driving) buff pattern (power performance). 114 indicates a water temperature sensor for detecting the engine cooling water temperature, and 116
118 is a foot brake, 118 is a brake switch that detects the operation of the handbrake, 120 is a CO rotation sensor that detects the rotation speed Nco of the clutch C0, and 121 is a CO rotation sensor that detects the rotation speed NC2 of the clutch C2. . FIG. 5 shows the main parts of the hydraulic control circuit 106. In FIG. 5, SLN is the linear solenoid valve for back pressure control, 208 is an accumulator control valve, 210 is a modulator valve, 212 is an accumulator for play 'r B 2, 214 is an accumulator for brake BO, and 216 is an accumulator for brake BO. Solenoid valve S
1 is a first shift valve for switching between a first gear and a second gear of the first transmission section 60, and 218 is a third shift valve for switching between high and low of the second transmission section 40 by a solenoid valve S3. Each shift valve is shown. Line pressure PL, generated in a known manner, is applied to port 210A of modulator valve 210 via oil passage 250. The modulator valve 210 receives this line pressure PL and generates a predetermined modulator pressure Pm at the same port 210A using a well-known method.4 The linear solenoid valve SLN receives this modulator pressure Pn and operates the first transmission section and The solenoid pressure PS+ is generated depending on the relative progress state of each shift in the second transmission section. This solenoid pressure PS+ is input to port 208A of accumulator control valve 208. The accumulator control valve 208 receives the throttle pressure pth from a throttle valve (not shown) and the solenoid pressure PS+ from the linear solenoid valve SLN as input signals, and regulates the line pressure PL of the boat 208B to the accumulator back pressure PaC. This accumulator backpressure PaC is the play'r B 2
It is simultaneously supplied to the back pressure chamber 212A of the accumulator 212 for the brake Bo and the back pressure chamber 214A of the accumulator 214 for the brake Bo. Now, when the computer 84 makes a shift decision (for example, a shift decision from the third gear to the second gear), the brake Bo is engaged and the brake B2 is drained by the following actions. First, to explain the engagement of the brake Bo, the third shift valve 218 is placed in the left-hand state in the figure by the solenoid valve S3. As a result, the line pressure PL input from the boat 218A is output from the boat 218B and begins to be supplied to the brake Bo via the orifices 252 and 254. During this supply, oil is also supplied to the accumulator 214 in addition to the brake Bo, so the piston 214B of the accumulator 214 starts to rise. While this piston 214B is rising, the brake B
The oil pressure P8° supplied to the piston 214C is maintained at a substantially constant oil pressure balanced with the downward biasing force of the spring 214C and the downward force acting on the piston 214B. The force pushing the piston 214B downward is the accumulator back pressure P related to the back pressure chamber 214A of the accumulator 214.
Generated by aC. Therefore, as described above, the accumulator back pressure Pac is
10, the linear solenoid valve SLN, and the accumulator control valve 208, it is possible to arbitrarily control the transient hydraulic pressure PIG when the brake Bo is engaged. Note that when the accumulator back pressure pac increases, the downward biasing force of the piston 214A increases accordingly, so that the transient oil pressure P@0 to the brake Bo increases, causing the engagement of the brake 'rBo, that is, the second The engagement (high gear shift) of the transmission section 40 is promoted. On the other hand, when the computer 84 determines a shift from the third gear to the second gear, the first shift valve 216 is switched by the solenoid valve Sl, resulting in the state on the right side of the figure. As a result, the oil passage 256 connected to the brake B2 is connected to the drain port 216A, so that the brake B2 is drained. In this case, the oil stored in the accumulator 212 will also be drained at the same time, but if the accumulator back pressure pac related to the back pressure chamber 212A of the accumulator 212 is strong, and therefore the piston 212B is pushed down with a strong force, Since the oil accumulated in the accumulator 212 is mainly drained, the oil pressure of the brake B2 does not decrease easily, and therefore, the drain of the brake B2, that is, the progress of the release (low gear shift) of the first shifter section 60 is delayed. It will be delayed. In this way, the increase in the accumulator back pressure pac functions to guide the progress of the speed change between the first transmission section 60 and the second transmission section 40 in the opposite direction. FIG. 6 shows a control flow executed in the apparatus of the above embodiment. In this control flow, for example, from the third gear to the second
A power-on downshift to a gear (downshift with the accelerator depressed) is shown. As described above, the downshift from the third gear to the second gear is performed by draining (releasing) the brake B2, causing the first transmission section 60 to shift to a low gear, and at the same time, the brake Bo is shifted to a low gear. second by being engaged
This is achieved by shifting the transmission section 40 to a high gear (see the engagement diagram in FIG. 3). First, in step 202, it is checked whether the power-on downshift is from the third gear to the second gear. If this is not the case, the process proceeds to step 204, where the target speed change process is performed and the process returns. If it is determined in step 202 that it is a power-on downshift from the third gear to the second gear, step 206
Go to and check 7 lag F for program control. Since this flag F is initially reset to zero, the process advances to step 208. In step 208, first play? A supply command for r B a (switching command for solenoid valve S3) is issued. Since it is a downshift, the release of brake B2 must be started first for the actual shift itself, but since the time lag between engagement and release is very large, brake B2 must be released first. The engagement command is issued first. In step 210, it is determined whether or not the delay time Ta has elapsed. If it has not elapsed, the flag F is set to 1 in step 212, and then the process returns. After returning, step 210 is performed again via steps 206 and 214.
The judgment is repeated. Eventually, the delay time Ta changes from the brake Bo supply command.
If it is determined that the period has not elapsed, the process proceeds to step 216, where a command to release the brake B2 (a command to switch the solenoid valve S1) is issued. In step 218, it is detected how much the speed change of the second transmission section 40 has progressed with respect to the progress of the speed change of the first transmission section 60, and if the speed change continues as it is, the speed change of the second transmission section 40 is It is predicted whether the end of the shift is likely to be delayed from the end of the shift of the second transmission section 60. Specifically, this prediction is performed by determining whether equation (1) holds true. Neon/ (l Neon -NcOr) -1l
) ＞(Non/ρ Nczn)/<Nczn
Nczn-+)... (1) Here, 80 indicates the rotation speed of clutch Co, NC2 indicates the rotation speed of clutch C2, and No indicates the rotation speed of the output shaft rotation speed (corresponding to vehicle speed). n indicates the value sampled this time, and y indicates the value sampled last time. Further, ρ indicates the number of teeth of the sun gear 61/the number of teeth of the ring gear 63. If formula (1) is established in step 218, that is, if it is predicted that the end of the shift of the second transmission section 40 will be delayed if this continues, the process proceeds to step 220 and the back pressure pac of the accumulator is increased by a predetermined amount. Therefore, the linear solenoid valve SLN is controlled. In this embodiment, in order to simplify control, the accumulator back pressure Pac is corrected only in the pressure increasing direction. Therefore, the initial value of this accumulator back pressure Pac (set depending on the throttle opening, etc.) is set slightly low. In step 222, it is determined whether or not the shifting of the second transmission section 4° has been completed. This determination is made by determining whether the current rotational speed Neon of the clutch C has become smaller than the constant ΔNeo. If it is determined that the shift of the second shift m section has not yet been completed, the process proceeds to step 224, where flag F is set to 2, and steps 218 and subsequent steps are repeated via steps 206 and 214. That is, 1, the accumulator back pressure Pac is increased until the shift of the second transmission section 40 is completed, and in step 218, the end of the shift of the second transmission section 40 is greater than the end of the shift of the first shift section a 60. It continues to run repeatedly as long as it is predicted to be late. By increasing the accumulator back pressure Pac, as described above, the speed change of the second transmission section 40 (engagement of the brake Bo) is accelerated, and at the same time, the speed change of the second transmission section 60 (drainage of the brake B2) is delayed. As a result, the imbalance in the current state of progress will be corrected. When it is determined in step 222 that the speed change of the second transmission section has been completed, the entire flow is ended. FIG. 7A shows a conventional speed change characteristic, and FIG. 7B shows a speed change characteristic when the above embodiment is implemented. This figure shows the power-on downshift characteristics from the third gear to the second gear at low speeds (vehicle speed around 30 kills). In conventional control, the shift time itself of the first transmission section 60 is short, especially in such a low speed region, so the high gear shift of the second transmission section 40 is started and completed during the low gear shift of the first transmission section 60. This is not easy, and as shown in the figure, an overshoot of the output shaft torque To occurs due to a delay in the end of the shift of the second transmission section 40. On the other hand, in this embodiment, this delayed state is detected and
Since the back pressure pac of the accumulator is increased, the second
The speed change of the transmission section 40 becomes faster, and conversely, the speed change of the first transmission section is delayed.
This can be hidden in the shifting of the transmission section 60, resulting in good shifting characteristics.

【Effect of the invention】

As explained above, according to the present invention, when a specific speed change is achieved by shifting each transmission section in opposite directions, only one linear solenoid valve can control the back pressure of the accumulator. 1 transmission section and 2nd
It is possible to shift the progress of the shifting of both transmission sections in the desired direction, and it is possible to always synchronize the end of shifting of both transmission sections regardless of various variations, and it has a simple configuration. This provides an excellent effect in that it becomes possible to obtain even better shift characteristics.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the gist of the present invention, and FIG. 2 is a block diagram showing the gist of the present invention.
A skeleton diagram of a vehicle automatic transmission to which the present invention is applied, FIG. Fig. 5 is a main hydraulic circuit diagram showing a part of the hydraulic control device in detail, and Fig. 6 is a block diagram showing an outline of the hydraulic control device. FIG. 7, a flowchart showing the control flow, is a line section showing the speed change characteristics when the above embodiment is executed in comparison with the conventional one. ...Engine, 0...Torque converter 1. 0...Second transmission section, O...First transmission section, 02...Vehicle speed sensor, LN...Linear solenoid valve for accumulator back pressure control.

Claims (1)

[Claims] (1) A shift control device for an automatic transmission in which first and second transmission sections capable of shifting independently are connected in series, and a specific shift is achieved by shifting each transmission section in opposite directions, means for simultaneously changing the back pressures of the respective accumulators of the frictional engagement devices involved in the above-mentioned speed change of both transmission sections; and means for predicting in real time whether or not the transmission section that shifts to a high gear is likely to be delayed relative to the end of the shift of the transmission section that shifts to a low gear. A speed change control device for an automatic transmission, characterized in that the back pressure of the accumulator is increased when it is predicted that the back pressure of the accumulator is increased.